1. Field of the Invention
The present invention relates to a display module used as a display device in a game machine, a digital camera, a portable terminal, or the like.
2. Description of the Related Art
In general, when a display panel such as a liquid crystal display panel (LCD) is incorporated into a product, a window that is a transparent plate is provided in the exterior of the product, and the display panel is disposed on the inner side thereof. This window functions as a protective plate that prevents the display panel from being damaged. Such a structure is used typically in digital cameras and mobile phones. In some game machines and portable terminals, a touch panel unit is disposed on the front side of a display panel.
When a display panel and a protective plate, or a display panel and a touch panel unit are disposed with an air layer therebetween, a reflecting surface due to the difference in refractive index is formed at the interface between a gas layer (air layer) and a solid layer (display panel, protective plate, touch panel unit). The formation of the reflecting surface decreases the visibility of the display panel. For example, the reflection of external light from the reflecting surface decreases the contrast of the display image, or the background mirrored in the reflecting surface overlaps the display image.
As a means to prevent the reflection at the interface between a gas layer and a solid layer, for example, a display device in which a display panel and a transparent protective plate are stuck together with at least one layer of transparent adhesive material therebetween is proposed (see Japanese Patent Laid-Open No. 2003-29644).
In addition, a display device in which a display panel and a tablet unit are stuck together with a transparent resin sheet therebetween, the adhesive power of the transparent resin sheet is 200 g/20 mm or less, and therefore the display panel and the tablet unit can be peeled and replaced is proposed (see Japanese Patent Laid-Open No. 8-327975).
Conventional display devices are disadvantageous in that if the display panel, protective plate, or touch panel unit (tablet unit) is damaged and repaired, the transparent adhesive material or transparent resin sheet needs to be removed and stuck again, and this increases the cost of replacement. That is to say, the transparent adhesive material or transparent resin sheet provided to improve the visibility causes a decrease in ease of assembling and disassembling in replacement work.